Method for connecting leadless chip package

Abstract

Leadless chip package is adhesively secured to printed wiring board and is electrically connected by metallic conductor ribbon or wire to pads on the package and pads on the printed wiring board to provide secure connected without risk of solder bridging on high density leadless chip packages.

What is claimed is: 
     
       1. The method for mounting and connecting a hermetically sealed leadless chip package with connection pads selected from the group consisting of gold and gold-plated copper on the top face thereof on a printed wiring board, comprising the steps of: positioning the hermetically sealed leadless chip package on the printed circuit board and attaching it thereto adjacent pads selected from the group consisting of gold and gold-plated copper on the exposed top face of the printed wiring board and orienting the leadless chip package so that the pads on the top face thereof are directed in the same direction as the pads on the exposed top face of the printed wiring board;   selecting a conductor from the group consisting of gold and gold-plated copper; and   attaching the electrical conductor to an upwardly facing pad on the chip carrier and to an adacent upwardly facing pad on the printed wiring board by means of an attachment step selected from the group of attachment steps consisting of:   ultrasonic welding, thermocompression bonding, ball bonding, wedge bonding and thermalsonic bonding.   
     
     
       2. The method of claim 1 including the step of: selecting the printed wiring board to be a fiber reinforced thermosetting adhesive printed wiring board, prior to the attachment step.   
     
     
       3. The method of claim 2 including the step of: selecting the conductor from the group consisting of conductors having a cross-section which is round, rectangular, triangular and oval.   
     
     
       4. The method of claim 1 including the step of: selecting the conductor from the group consisting of conductors having a cross-section which is round, rectangular, triangular and oval.   
     
     
       5. The method of claim 1 including the step of: securing the chip carrier package to the top face of the printed wiring board by adhesive attachment.   
     
     
       6. The method of claim 5 wherein the step of securing the hermetically sealed leadless chip carrier package to the top face of the printed wiring board is by adhesive securement. 
     
     
       7. The method of claim 5 wherein the step of securing the chip carrier package to the top face of the printed wiring board is by adhesive securement. 
     
     
       8. The article produced by the method of claim 7. 
     
     
       9. The method of claim 1 including a step of cleaning the printed wiring board and the leadless chip package is performed before the step of electrically interconnecting the pads by attachment of conductors therebetween. 
     
     
       10. The method of claim 1 including the step of: extending pads from the bottom to the top of the hermetically sealed leadless chip package and the extending step is performed before the positioning step so that there are pads on the hermetically sealed leadless chip carrier package facing both the top face of the printed wiring board and facing in the same direction as pads on the printed wiring board.   
     
     
       11. The article produced by the method of claim 1. 
     
     
       12. The method of connecting a hermetically sealed leadless chip package on a printed wiring board comprising the steps of: printing wiring on a fiber reinforced thermosetting synthetic material board with conductive connection pads on a top face thereof;   forming a hermetically sealed leadless chip package so that the chip package has conductive connection pads on a top surface thereof positioned adjacent to an edge of a surface opposite a bottom surface thereof;   positioning the hermetically sealed leadless chip package with its bottom surface on the top face of the printed wiring board so that the connection pads on the hermetically sealed leadless chip package face in the same direction as the connection pads on the printed wiring board;   adhesively securing the hermetically sealed leadless chip package in place with its bottom surface on the top face of the printed wiring board;   bonding a metallic conductor to a connection pad on the hermetically sealed leadless chip package and bonding the same metallic conductor to a corresponding connection pad on the printed wiring board; and   repeating the bonding steps for a plurality of connection pads on the hermetically sealed leadless chip package so that the circuitry of the hermetically sealed leadless chip package is connected to the connection pads on the printed wiring board.   
     
     
       13. The method of claim 12 wherein the bonding step is selected from the group of bonding steps consisting of: ultrasonic welding, thermocompression bonding, ball bonding wedge bonding and thermalsonic bonding.   
     
     
       14. The method of claim 12 wherein the bonding of an electrical conductor is performed with a metallic wire selected from the group consisting of gold and gold plated copper. 
     
     
       15. The method of claim 12 wherein the step of forming the pads on the hermetically sealed leadless chip package includes the step of forming the pads so that they are present on both the top and bottom surfaces of the hermetically sealed leadless chip package. 
     
     
       16. The article produced by the method of claim 15. 
     
     
       17. The article produced by the method of claim 12.